Experimental Research for Operating Thermal Electric Plant Ash in Coating Powder Production Used in the Continuous Steel Casting Lines

In this paper the authors present obtaining of a technological powder used for the continuous casting of steel. The powder is applied in the casting plant distributor to ensure thermal insulation, prevent oxidation of the steel and especially to capture the steel inclusions. The powder helps to purify the steel and thus improve its quality. The paper presents the physical and chemical characteristics of the power plant ash, which is a fine-grained waste, stored in dumps and which can be used for the production of coating powders. Several experimental recipes were made, in which the proportion of power plant ash was between 65-80%. To characterize the recipes, measurements were made to determine the humidity, volumetric mass, spread area, particle size analysis, melting temperature and chemical analysis. After analyzing the physical, chemical and thermal characteristics, pilot experimental batches were performed for testing in the steelworks. The favourable effects of the use of Cenoterm powder were highlighted by analyzing the slag samples taken from the experimental batches. These showed an increase in the MnO content of steel up to 30%, an increase in alumina, magnesium and a decrease in silica. They show that the molten powders in the formed slag are reactive and play a beneficial role in the quality of the steel. Consumption of ash-based coating powder was between 0.065 and 0.22 kg/t liquid steel

Ecotechnologies – A Major Route for DurableSustainable Development in the Metal Materials Industry

The paper shows that the durable and sustainable development depends on the quality of the events occurring in the convergence area between the natural ecological system (N.E.S.) and the technological system (T.S.) represented by the metal materials industry. The analysis is carried out in the following situations: - decrease in the level of negentropy (nS) of N.E.S., due to the consumption of natural resources by T.S., and - increase in the level of entropy (S) of N.E.S., due to the discharge into the environment of the pollutants generated by T.S. Ecotechnologies constitute a major tool for optimizing the correlations N.E.S.-T.S. Our study proposes a classification of ecotechnologies in four categories, according to their influence on nS and S. The role of ecotechnologies in reducing the environmental entropisation phenomenon is also highlighted

High-Strength and Heat-Insulating Cellular Building Concrete Based on Calcined Gypsum

A cellular concrete with a fine porous structure was experimentally made using the corrosion technique for aluminum powder as an expanding agent in an aqueous solution of Ca(OH)2. The originality of this paper was the use of our own production method for the fine aluminum powder through atomizing the recycled molten waste of this metal using concentrated jets of nitrogen. Additionally, the waste melting technique involved our own microwave heating method. A high weight proportion of calcined gypsum (maximum 82.3%) represented the main concrete binder. Using moderate contents of coal fly ash (3.6–11.1%) together with perlite (4.6–6.4%) to reduce the pore size and silica fume (0.3–1.2%) with pozzolanic properties, the aim was to obtain a macrostructure characterized by a very low pore size and to increase the compressive strength (by up to 4.1 MPa), despite the relatively low density (below 641 kg/m3). An industrial method of increasing the mechanical strength by steam curing fresh concrete was applied